Why does a fancy rat not walk around in his ball?

A fancy rat may not walk around in its exercise ball due to several reasons, including fear or discomfort with the enclosed space. The ball can also restrict their natural behavior and instinct to explore, leading to stress. Additionally, if the ball is too large or too small, it may hinder their movement, causing them to avoid using it altogether. Providing a safe, open environment for exploration is often more beneficial for their well-being.